Safety device for presses



H. A. DAVENPORT.

SAFETY DEVICE FOR PRESSES.

APPLICATION FILED OCT. 30, I919.

Patented Dec. 6, 1921.

' is o HUDSON A. DAVENPORT, or wvaiiinorrn, nineteen, ASSIGNOR or ONE-THIRD ro FREDERICK RsrRAeUE, or WYANDOTTE, MICHIGAN, AND ONE-THIRD 'ro HARRY. e. MORRISON, or 'rnnnron, MICHIGAN. I

SAFETY DEVICE FOR PRESSES.

To all w/wmit may concern:

Be it known that'I, HUDSON A. DAVEN- ron'r, a citizen of the United States of America, residing at l Vyandotte, in the county of Wayne and State of Michigan,

have invented certain new and useful Improvements in Safety Devices for Presses, of which the following is a specification, reference being had therein to the accompanying drawings.

In the operation of punch presses'and' other machines having reciprocable rams, plungers and similar members, and more particularly those machines constructed for repeat operations, there is alwaysdanger of the operator or attendant of the Imachine nwith positive and reliable means,ina manner ashereinafter set forth, for blocking or chucking a press or similar machineso that the ram or reciprocable memberthereof cannot reciprocate unless the operator or attendant of the machine is prepared for such operation. F

Another object of my invention is to fur nish a punch press or similar machine with anovel chuck block which is operated in synchronismwith the lever of the punch press and automatically released so that the chuck block will at all times be in position to prevent a repeat operation of the punch press, and thus eliminate such accidents as an operator or attendant having the-hands or parts of the body injured by dies or the actuated parts of the punchpress. Q a

A still further object of my inventionis to provide a safetydevice that maybe easily and quickly installed in connection with ordinary punch presses, the device being simple in construction, durable andhighly ellicient for the purposes'for which it is intended.

The above and other objects are attained by a mechanical construction which will be hereinafter specifically described and then claimed, and reference will now be had to the drawing, Wherein j Figure leis a side elevation of'the safety Specification of Letters Patent.

Patented Dec. 6, 1921.

Application filed October 30, 1919. Serial NO. 834,560.

device as applied to a portion of a Fig. 2 is a plan of the safetydevicashowpunch I ing a portion of the punch press in section, V

and

Fig. S'is a side elevation of a portion of the safety device illustrating an automatic release in connection with the same.

In the drawing there is illustrated a conventional form of punch press as including a base 1, a bed 2, a frame 3, and a reciprocable ram or member 4. It is betweenthe bed2 and the ram 4 that diesior any other members maybe placed so that the various kinds of work can beperformed by pressure; This type of machine is capable of having its ram repeatedly reclprocated and the operation of the ram is ordinarily controlled by a reach rod 5 and atrip lever or pedal 6, the latter being pivotally connected to the base 1 so that the Operator or attendant 'of the machine can control the operation of the machine by foot pressure,

thus leaving the hands free to manipulate a piece of work beneath the ram 4;

Suitably attached to the rear side of the base 1 is a bracket 7 and mounted on the bracket 7 is a housing 8 having parallel side walls 9. Connecting the lower portions of the side walls 9 are pivot pins 10 for arms 11 and 12, said arms having the upper ends thereof pivotally mounted by trans-v verse pins 13 in slots or bifurcations 14 of a shiftable block holder 15, said block holder being disposed in a horizontal plane between the upper edges of-the housing walls 9. The

outer end of the block holder 15 is bifuris detachably clamped in the block holder so that it. may be removed and blocks of different sizes placed therein, thus'permit ting of the safety device being used in con- I nection with machines having variable ram strokes.

The arm 11 is of greater length than the arm 12 and the arm 11 has a slot 18- in its upper end through which extends the block pin 13, saidpin being engaged by a coiled compression spring 19 within the slot. The

expansive force Of the spring 10 holds the pin 13 normally in the lower end of the slot 18, but when the block 17 is struckby the ram 4 and the outer end of the holder 15 is tilted, then the inner end of the holder may swing upwardly with the pin 13 of the arm 12 serving as a pivot for the holder, thus releasing the arm 11 of stresses and strains due to the block 17 being struck by the ram said keeper are the hook shaped ends of latches 21 and 22, the former being in latter resting against the keeper to assume a locked position" when the keeper is shifted. The latch 22 is pivotally supported, as at 23, from one of the side walls 9 of the housing 8, and the latch 21 is pivotally connected to an arm 24 on a transverse bearing pin 25, carried by the housing walls 9. The lower end of the fulcrumed arm 24 extends below the housing 8 and through the bracket.

7 for connection with a link 26 which is connected to a crank 27 on the pivoted end of the trip lever or pedal 6, and in consequence of the latch 21 being in positive engagement with the keeper 20, the block holder 15 will be retracted when the trip lever 6 is actuated. Such an operation will withdraw the chuck block 17 from below the ram 4 and permit the ram to descend, providing the trip lever 6 is fully actuated, otherwise a coiled retractile spring 28 below the block holder 15, retains the block 17 beneath the ram 4. The spring 28 is connected to a depending lug 29 of the holder 15 and to a transverse rod 30 connecting the housing walls 9.

WVhen the block holder 15 is retracted the latch 22 is raised to pass through the keeper 20 and lock the keeper in a retracted position, but the latches 22 and 21 are adapted to be raised to release the keeper 20 by the crank portion 34 of a ram operated arm'32 pivotally connected to one ofthe housing walls 9, as at 33, this ram lever'having its outer end curved beneath the ram 4 and normally held in engagement therewith by a coiled retractile spring 31 connecting the inner end of the lever to one of the housing walls .9. e a

In operation, pressure on the trip lever 6 will place the punch press in operation so.

that the ram 4 may descend, and simultaneous with the depression of the trip lever 6 the keeper 20 of the block holder 15 is retracted, causing the block holder to remove its block 17 from beneath the ram 4, so that said ram may descend and result in anoperation being performed by the machine. As pointed out before, the latch 22-will momentarily engage the keeper 20 and hold the keeper so that the ram 4 can descend before the blockv 17 has a chance to interfere with its operation, but after the ram 4 ation of the punch press. locked engagement with the keeper and the block.

Where the ram 4 has a short stroke the latch 22 will temporarily hold the block 17 i so that the blockcannot return before the ram 4 is in position to prevent complete return movement, and it may be found that in connectionwith other types of presses it will be unnecessary to use the latch 22 and its operating mechanism.

It is thought that the operation and utility of my safety device will be apparent without further description, and while in the drawing there is illustrated a preferred embodiment of the same, it is to be under stood that the structural elements are susceptible to such variations and modifications as fall within the claims; v

What I claim is: r

1. The combination with a machine, having a reciprocable'member, and a lever for controlling the operation of said member, of a housing, a holder bodily movable in scope of the appended said housing and to and from said machine,

and tiltable in a vertical plane relative to the machine, a block carried by said holder and normally in the path of said member, a latch normally-engaging said holder, means supported from said housing connecting said latch to said lever so that said latch may be operated to retract said holder when said lever is depressed, and means parallel to;

said latch and supported from said housing adapted to temporarily hold said holder until said member is in the path of said 2. Meansadapted to prevent arepeat operation of a press having a reciprocable ram, 1

comprising a block normally in the path of said ram and adapted to be retracted and so held by engaging the :side of the ram, supporting means forsaid block permitting of said block self seating when struck by the ram to relieve said supporting means of strainsincident to the'blow by the ram, and

meansoperated by placing the press in operation to retract said block. a

Means adapted to prevent a repeat operation of a press having a reciprocable ram,

comprising a housin for attachment to a press, a block norma ly in the path of the ram and yieldably supported from within said housing, means in said housing for shifting said block longitudinally thereof, y

and means operated by placing the press in operation to actuate the means within said housin p 4. l\ eans adapted to prevent a repeat operation of a press having a reciprocable ram, comprising a housing for attachment to a press, substantially parallel arms pivoted in said housing, a holder pivotally sup ported by one of said arms and loosely held by the other of said arms and extending into the path of said ram, latch mechanism adaptedto retract said holder, latch in'ech anism adapted to temporarily hold said holder retracted, and means supported independent of said ram actuated by the ram 15 to release said latch mechanisms.

In testimony whereof I afiix my signature in the presence of two witnesses.

HUDSON A. DAVENPORT. Witnesses: I

KARL H. BUTLER, ANNA M. Donn. 

